Gold Standard Gravity
---- Acknowledgements -----
A much earlier version of a portion of this work was presented at the NBER ITI meetings, Spring 2010 and the Venice Trade Costs conference, June 2010. We thank participants for helpful comments, especially Dave Donaldson, Keith Head and Michael Waugh. We also thank Arthur Lewbel for helpful comments. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.